Irrigation could create conditions that attract plant pests

The use of irrigation across Sub-Saharan Africa creates conditions that attract devastating foreign plant pests such as the tomato leaf miner, a Kenyan study has found. This was reported by SciDev.Net in August 2015. The study “Identification and risk assessment for worldwide invasion and spread of Tuta absoluta with a focus on Sub-Saharan Africa: implications for phytosanitary measures and management” was published in the journal PLOS One in the same month.

East Africa is at particular risk of infestations from the moth, as temperatures and seasonal rainfall in the region increase due to climate change, the researchers warn. They discovered that the increasingly frequent watering of fields turns more areas into suitable habitats for the destructive insect.

As well as tomatoes, the tomato leaf miner attacks crops such as potatoes, peppers, eggplants (brinjal) and tobacco. Native to South America, the pest reached Europe in 2006 and has since spread across the Middle East into Africa.

The study describes how rainfall in Africa is likely to increase by ten per cent over the next two decades under the latest climate-change predictions, while temperatures are set to rise by 1.5 degrees Celsius. Coupled with rising irrigation, this will create a warm and moist environment in which crop-eating insects from other tropical countries and continents can thrive.

For example, the climate of the tomato leaf miner’s original habitat in South America is similar to the climate developing across large parts of Africa. 

The study is the first time that irrigation has been included as an indicator for pest spread, the researchers say, and gives a more realistic picture of their expected spread.

The Kenyan researchers are now trying to help affected farmers by training them to manage the pest by introducing natural predators.

Read the article: Identification and risk assessment for worldwide invasion and spread of Tuta absoluta with a focus on Sub-Saharan Africa: implications for phytosanitary measures and management (PLOS One, 7 August 2015)

(Ines Nastali, SciDev/ile)